This invention relates to fluid pressure generators and more particularly pertains to an apparatus and method for producing a high pressure thermal vapor stream comprised of steam and combustion gases, carbon dioxide, nitrogen, water, sulfur dioxide, and other combustion products, for injection into a subterranean formation, particularly a petroleum-bearing formation, for the recovery of liquefiable minerals therefrom.
Apparatus for producing a pressurized thermal fluid stream comprised of mixtures of steam and combustion gases and for injecting such streams into a subsurface formation for recovering liquefiable minerals, e.g., sulfur, mercury, gilsonite, heavy viscous petroleum and the like have heretofore been disclosed in the prior art. Examples of some such apparatus are described in the following patents, to name a few: U.S. Pat. Nos. 3,620,571; 2,916,877; 2,839,141; 2,793,497; 2,823,752; 2,734,578; 2,754,098 and Mexican Pat. No. 105,472.
So far as known, the prior art thermal vapor producing apparatus have not been satisfactory for producing sufficient quantities of high pressure thermal vapors of steam and combustion gases for sufficient time periods for injection into a subsurface formation for economical recovery of highly viscous petroleum therefrom. Some of the high pressure combustion chambers of these apparatus are incapable of complete combustion of hydrocarbon fuels in the presence of the stream of high pressure air injected therein. This results in the formation of a partially combusted gas stream which contains harmful oxidizing components such as nitrous oxides, carbon monoxide, etc., as well as solid carbonaceous particles, i.e. soot. As known, these gases may be extremely harmful in that they may cause undesirable reactions with the liquefiable minerals being recovered, particularly viscous petroleum. Additionally, the soot may collect in the pressurized combustion chamber and steam generating vessel thereby causing frequent mechanical breakdowns. The soot may also be carried over to plug the well and formation. Furthermore, as far as known, most prior art apparatuses having sufficient size cannot be operated continuously for extended lengths of time, as usually required in economical injection techniques for recovery of the petroleum, without suffering mechanical breakdown due to overheating and burning out of the pressurized combustion chamber.
It is well-known that in order to provide economical recovery of liquefiable minerals large volumes of a thermal fluid must be generated and injected into the formation. This is particularly true in techniques for the recovery of viscous petroleum wherein the thermal fluid is usually continuously produced and injected into a petroleum-bearing formation over a period of from several hours to several days and even months. Additionally, in such techniques for the recovery of petroleum, the thermal fluid must be injected into the subterranean formation under pressures higher than the formation pressure. However, so far as is known, no one previously has provided a satisfactory apparatus for producing and injecting a high pressure thermal vapor stream comprised of steam and combustion gases in sufficiently high volumes and under sufficiently high pressure to provide satisfactory economic recovery of the viscous petroleum. Since there are large quantities of hithertofore unproducible crude petroleum, this invention becomes very important in times when all available fossil fuels are needed.